my %hash = ();

while (my $row_ref = $sth->fetchrow_arrayref) {
        my $date = @$row_ref[1];
        my $samples = @$row_ref[2];

        $hash{$date} = $samples;
}


for(my $i = $days;$i >= 1;$i--){
        my $myseconds = time - ($i * 86400);
        (my $sec, my $min, my $hour, my $mday, my $mon, my $year, my $wday, my $yday, my $isdst) = localtime($myseconds);

        $year = $year+1900;
        $mon = $mon+1;

        if($mon<10){
                $mon = "0$mon";
        }
        if($mday<10){
                $mday="0$mday";
        }
        my $mydate = $year. "-" .$mon. "-" .$mday;

        print $mydate ." samples: ";
        if(exists $hash{$mydate}){
                print $hash{$mydate};
        } else {
                print "No samples";
        }
        print "\n";